This invention relates to certain Group 4 metal complexes comprising a cyclic, or noncyclic, non-aromatic, anionic, dienyl group wherein the metal of said complexes is in the +2 or +4 formal oxidation state and further wherein the metal is also covalently bonded via a second ligand group to the cyclic or noncyclic, non-aromatic, anionic, dienyl ligand group. The invention also relates to techniques for preparing such complexes, catalyst systems comprising such complexes that are useful for polymerizing addition polymerizable monomers, and to such polymerization processes themselves.
Metal complexes containing delocalized, n-bonded ligand groups and methods for their preparation are disclosed in U.S. application Ser. No. 545,403, filed Jul. 3, 1990 (EP-A-416,815); U.S. application Ser. No. 547,718, filed Jul. 3, 1990 now abn (EP-A-468,651); U.S. application Ser. No. 702,475, filed May 20, 1991 now abn (EP-A-514,828); U.S. application Ser. No. 876,268, filed May 1, 1992, (EP-A-520,732) and U.S. application Ser. No. 8,003, filed Jan. 21, 1993 now U.S. Pat. No. 5,374,696 (WO93/19104), as well as U.S. Pat. No. 5,055,438, U.S. Pat. No. 5,057,475, U.S. Pat. No. 5,096,867, U.S. Pat. No. 5,064,802 and U.S. Pat. No. 5,132,380. The teachings of all the foregoing patents, publications and patent applications are hereby incorporated by reference.
Despite the advance in the art brought about by the foregoing metal complexes, new and improved catalytic compounds are still desired.